Assessment of Occupants’ Thermal Condition and the Risk of Overheating in Sustainable Public Libraries in Auckland Region

This paper examines the thermal condition of occupants and the risk of overheating in two award winning sustainable public libraries in Auckland region of New Zealand through long term environmental monitoring of the building performance and occupants’ survey. The survey was performed on eight staff of the library who have occupied the buildings for more than two years. The data were further contrasted with the risk of overheating assessment which were based on thermal comfort design parameters for free-running buildings. The standards that define the risk of overheating used in this study are CIBSE A 2006 standard the British Standard EN 1525; the TM52 CIBSE; and Building Bulleting 101 (BB101). The results demonstrate that none of the libraries are at the risk of overheating during the summer season. However, the building occupants claimed that in certain periods, the buildings can get overheated, even though, adaptive comfort criteria was used to design these libraries. The discrepancies between the overheating risk methods and the surveys can be further explained by the fact that none of the overheating methods considered the effects of the water content in the air. Such parameter is proven to have an effect on the capacity of the body to reduce its own temperature though the evaporative effect in the skin. Therefore, a standard that takes into account the humidity ratio such as the ASHRAE 55 might shed light to understand the thermal comfort responses of the occupants. The study provides insight into the socio-technical issues in overheating risk assessment in the context of public libraries in temperate climates.